Trimmer string size

Discussion in 'Lawn Mowing' started by Ronbo, Aug 9, 2003.

  1. Ronbo

    Ronbo LawnSite Member
    from Indiana
    Posts: 3

    Could anyone give me some advice on string size for the application, like what is small diameter best for and so on.
     
  2. ElephantNest

    ElephantNest LawnSite Bronze Member
    from La.
    Posts: 1,878

    Small ( .75, .85, etc.) is for smaller trimmers with smaller engines. .95 and up is for larger trimmers with larger engines. I run .85 diamond edge or gator line square with both the Shin 270, 230, and the echos.

    ~Nest
     
  3. Ronbo

    Ronbo LawnSite Member
    from Indiana
    Posts: 3

    Thanks, wasn't sure if it was for grass versus weeds.
     
  4. Doc Pete

    Doc Pete LawnSite Gold Member
    Posts: 3,469

    Hmmmmmm, I believe line thickness is more for the application rather than motor size. IMO, if you want to trim (cut) grass, you want the fastest tip speed you can get, after all this is what you want in a mower, isn’t it??.
    I use .065 line and a bent shaft trimmer. Bent shaft trimmers are all “direct drive”, while all straight shaft trimmers are gear drive, which are a 30% gear reduction and result in a similar rpm drop. This is one reason I use a bent shaft machine, because of its inherent faster shaft rpm.
    Faster tip speed cuts the grass rather than tearing it and turning it brown a day later, just like dull blades do on a mower.
    OK, smaller diameter line also has much less drag which makes it easier to allow faster rpm. And naturally, with less drag you can run a larger cut diameter, increasing the tip speed even more. It’s a win win situation. Furthermore, smaller line also creates less turbulence and does not “blow down” the grass you intend to trim, which forces many operators to scalp the trimming area in order to actually cut the grass.
    All other choices for line diameter should similarly be based on “quality of cut verses longevity”. Simply put, the thicker the line the longer it lasts, and the poorer the cut quality. It’s not rocket science were dealing with.
     
  5. thartz

    thartz LawnSite Senior Member
    Posts: 486

    Switchless;If I used .065 line we would run through that at 1 full line spool a day.I used .095 spool and that seems to be a happy medium.I use units that have a clutch system if that makes any difference.These engines are 23cc and 26 cc.The heavier line seems to help the head not vibrate as much.You can tell when the head is full of line verses being close to empty.Your dealer will help in being your best advisor.
     
  6. Doc Pete

    Doc Pete LawnSite Gold Member
    Posts: 3,469

    Yes, I can't agree more.... Again, the line should be more suited to the application, which also means how long the lines lasts. Doing only grass trimming with my machine and .065 line I can trim about 40 average 1/2 acre accounts before I run out. Furthmore, besides preloaded spools, I carry an extra head loaded with heavier line for a quick change, when have long runs of sidewalk, driveway or similar " heavy wear" situations.
    Pete
     
  7. thartz

    thartz LawnSite Senior Member
    Posts: 486

    Pete; I'm with you! but if my guys trim the concrete edges and lanscape beds with .065 that would really kill the profit margin.BTW I have to apologize to you on the 45 degree deal;most the DOT specs we mow are graded at 35 to 37.i can't guarentee 45;my mistake.We do 3 lawns that I sighted (one being my own home;wait till I get a digital camera because that was one of the selling points for me) and they all fall around 37 degrees except for mine.Mine is a true 45.Cuts the mower out about every 10 feet.
     
  8. ElephantNest

    ElephantNest LawnSite Bronze Member
    from La.
    Posts: 1,878

    If I use .65, I go through it 3 times as fast as .95. Also, no matter what the application, on my 270 and now the new 230, .65 winds the motor way too high, too light of a string for such power, and the dealer advised me of this. And forget doing thick weeds, like an account of mine along a highway where it must be weedeated, .65 wouldn't hang. Homelite:.65 Real power: .85+

    IMHO

    ~Nest
     
  9. Like everyone says, it depends. The key to efficient smooth cutting is high rpms. If your trimmer motor cant spin heavy line fast, it is better to go smaller. If you’re cutting grass, go with Sufix. If you’re cutting thick weeds or reeds, go with Gator Line Magnum.
     
  10. Doc Pete

    Doc Pete LawnSite Gold Member
    Posts: 3,469

    First, I agree with what you say, however, as I thought I made clear, the size should be decided by the application it's being used for. Also, everyone is talking about gear drive trimmers, which right from the get go is "designed for power" and not speed. So, with that in mind, like a diesel motor, you want use it's power, by lengthening the line to increase tip speed, which also entails running without a guard (let’s not get into that post).
    Along these lines, using a big, highpowered heavy trimmer for cutting normal grass is already the wrong tool for the job. As a professional you should have at least 2 trimmers (or spare thick spooled head), one for grass cutting and one for "brush hogging". That's why I have 3 trmmers and an extra head just for heavier work. Actually, if you are doing a lot of heavy brush and/or weeds, a cheap trim motor is a much better tool for the job.
     

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